Many attachments allow your excavator to efficiently handle irregular-shaped objects, including thumbs and grapples. The first step is to assess whether you really need a grapple or if you could be just as productive with a bucket and thumb.
The bucket/thumb combination can handle most tasks. "If you handle a lot of different material over a wide range of applications, a bucket with a thumb will do the job eight times out of 10," says Bo Pratt, marketing manager, Rockland Mfg.
So the choice really boils down to the efficiency in your particular operation. "The contractor's grapple will typically be much more productive in most applications (demolition, rock handling, scrap handling, land clearing, etc.)," says Uwe Kausch, product line manager, Stanley LaBounty. "You should use a grapple if a good part of your business is anything other than dirt. For demolition and serious material handling, the grapple is the way to go."
Pratt agrees, adding, "The productivity is going to be much better with a grapple if you are handling the same material over and over and you don't have to dig with your machine." He attributes this to the ability of a grapple to grab more material in a pass than with the bucket/thumb combination.
Grapples also tend to work better on irregular objects. "Some items grapples can lift easily are hard pressed to fit between a bucket and thumb combo," says Tracy Black, operations manager, Kenco. "In many situations, grapples are used to allow soil and small rocks to fall through to the ground. This cuts down on the amount of material moved, thus saving time and money. Buckets tend to retain more unwanted material. Grapples offer more precise picking options, as well."
"However, if a contractor is foremost a dirt contractor and only occasionally needs to handle material or do smaller demolition jobs, then a bucket/thumb combination may be better suited to him," says Kausch. "The bucket/thumb is also better suited if he is trenching and needs to remove rocks from a trench and other applications where the material is very fine."
Selecting a grapple
After you have determined that a grapple is the best choice, you must choose the right one for your application. The simplest configuration is the contractor's grapple. Contractor's grapples feature a stationary jaw and an upper jaw that operates off the bucket cylinder. "It is very simple to use and does not require any additional hydraulics," says Kausch.
"The fewer hydraulic functions you have on a grapple, the easier it will be to use and the more reliable the grapple will be," notes Pratt. The end result is the contractor's grapple costs a lot less and there is less maintenance. "It has been our experience that if a contractor is handling the same material over and over, then a fixed-jaw grapple will meet his or her needs." However, if the application demands precise material handling, a rotating grapple may be the better choice.
Rotating grapples require auxiliary hydraulic circuits. "The advantage with the rotating grapple is that they are better suited for applications where precise picking, sorting and placement are necessary," says Kausch. "For example, in applications where timbers or structural steel is to be salvaged, the rotational ability allows the operator to get a better handle on the piece. It also excels in applications such as rock rip-rapping, and it can do a more efficient job in loading trucks. (The operator doesn't need to be at a 90° angle)."
Less time is spent maneuvering the excavator. "The operator can position the grapple without moving the machine," says Black. "In the right job situation, these grapples can outperform any fixed grapple. The down side is with hydraulics and rotators the price goes up. The contractor must weigh the initial cost vs. the expected gain."
Dual-acting cylinders also provide the grapple with extra dexterity. Stanley LaBounty has designed a link to synchronize the opening and closing of the tines. "We have found this to be advantageous with most applications, and it makes it easier for the operator," says Kausch.